دانلود Impact of Carrier-Grade NAT on web browsing

Abstract

Public IPv4 addresses are a scarce resource. WhileIPv6  adoption  is  lagging,  Network  Address  Translation  (NAT)technologies  have  been  deployed  over  the  last  years  to  alleviateIPv4  exiguity  and  their  high  rental  cost.  In  particular,  Carrier-Grade  NAT  (CGN)  is  a  well  known  solution  to  mask  a  whole ISP  network  behind  a  limited  amount  of  public  IP  addresses, significantly  reducing  expenses. Despite its economical benefits, CGN can introduce connectivity issues which have sprouted a considerable effort in research, development  and  standardization.  However,  to  the  best  of  our knowledge,  little  effort  has  been  dedicated  to  investigate  the impact  that  CGN  deployment  may  have  on  users’  traffic.  This paper  fills  the  gap.  We  leverage  passive  measurements  from an  ISP  network  deploying  CGN  and,  by  means  of  the  Jensen-Shannon  divergence,  we  contrast  several  performance  metrics considering customers being offered public or private addresses. In  particular,  we  gauge  the  impact  of  CGN  presence  on  users’ web  browsing  experience. Our results testify that CGN is a mature and stable technology as,  if  properly  deployed,  it  does  not  harm  users’  web  browsing experience.   Indeed,   while   our   analysis   lets   emerge   expected stochastic  differences  of  certain  indexes  (e.g.,  the  difference  in the  path  hop  count),  the  measurements  related  to  the  quality of  users’  browsing  are  otherwise  unperturbed.  Interestingly,  we also observe that CGN protects customers from unsolicited, often malicious,  traffic.